1. Field of the Invention
This invention relates to a system for refilling a dispensing cartridge with material made of one or more components.
2. Description of the Related Art
Dispensers are used in a variety of fields for applying a liquid or semi-liquid material directly to a work site or other area as desired. Dispensers that are adapted for hand-held use are especially advantageous because the dispenser can be maneuvered as needed to apply the dispensed material at a particular location. However, the amount of material contained in hand-held dispensers is somewhat limited, because the material together with the container should not weigh more than the hand can comfortably carry.
Some dispensers include replaceable cartridges that contain the material to be dispensed. Examples include caulking guns and other applicators for home, construction or industrial use, and certain syringes and dispensers used in medical and dental fields. The use of cartridges is often considered convenient because contact with the material in the cartridges can be avoided. Unfortunately, such cartridges are often not recycled and consequently contribute to problems associated with solid waste. Purchasing material in cartridges is also somewhat costly due to the cost of the cartridge and the relatively small amount of material contained in the cartridge.
Dispensers having cartridges with dual chambers are typically used to dispense material made of two or more components. In many instances, the dispenser includes an exit conduit that is coupled to outlets of the chambers. The exit conduit contains a static mixer (or optionally a dynamic mixer) for mixing the components during passage through the exit conduit, so that hand mixing can be avoided.
Examples of dual chamber cartridge dispensers are described in U.S. Pat. Nos. 4,995,540 and 5,005,735. In general, such dispensers include a pair of side-by-side plungers that are advanced by a ratchet mechanism to simultaneously push respective pistons in the chambers of the cartridge and direct the components in both chambers toward the exit conduit containing the mixer. Linkage of the pistons together helps insure that the components are discharged and mixed in the proper ratio (such as 1:1) as might be specified by the manufacturer.
Dual chamber cartridge dispensers are widely used in the field of dentistry to deliver impression material to an impression tray or, on occasion, directly into the oral cavity. Recently, there has also been increased interest in using dual chamber cartridge dispensers in the field of audiology for dispensing material used in taking an impression of the outer ear canal in order to make a custom-fitted hearing aid. Dispensers having dual chamber cartridges are also used in construction fields, automotive trades and industrial applications for dispensing materials such as epoxies, sealers and coatings made of two or more components that are mixed immediately before use or application.
The use of dual chamber cartridge dispensers for mixing and dispensing material made of two components helps avoid problems often associated with estimation and hand mixing of components provided in separate tubs, tubes or other types of containers. Additionally, human contact with the components or the mixed material need not occur when using such dispensers, an advantage from the standpoint of infection control in the medical or dental fields because the potential for contamination of the components or material is reduced. Reduction of human contact with the components or the mixed material also reduces the likelihood of an allergic or toxic reaction.
However, dual chamber cartridges, like single chamber cartridges, are normally disposed of after a single use and as such create problems associated with solid waste. Furthermore, there is often a small amount of material that remains in the used cartridge that cannot be ejected by the dispenser.
Another disadvantage associated with cartridge dispensing systems occurs during instances when the cartridge is not completely full at the beginning of the dispensing operation, and the need arises to replace the cartridge mid-way through the dispensing operation. Interruption of the dispensing operation to replace the cartridge is often inconvenient and may unduly reduce the opportunity to work with the material as might be desired before setting or curing occurs.